1. Field of the Invention
The present invention relates to above-the-ground swimming pools. More specifically, the present invention relates to methods and apparatus for a large capacity reinforced swimming pool for use above-the-ground which includes a continuous reinforcing layer bonded to a sidewall with a first plurality of reinforcing seals and a second plurality of reinforcing seals for reinforcing the sidewall against failing due to excessive water pressure.
2. Description of the Prior Art
The prior art is directed to methods and apparatus for above-the-ground, large capacity swimming pools formed from flexible polymeric sheeting such as polyvinylchloride and typically used in the out-of-doors.
The science of dielectrically or Radio Frequency (RF) sealing polymeric or polyvinylchloride (PVC) materials of the prior art is well known in the plastics industry. The use of PVC sheeting for both in-the-ground and above-the-ground pool liners has become more popular in recent years. The initial applications of these pool liners originated with the PVC sheeting being used as pond and ditch liners. However, the uses of PVC sheeting has been expanded. As the strength of above-the-ground pool liners improved (including those supported by a skeletonal metal or plastic framework and those that were unsupported), the greater the depth of water the prior art pool liners could support. As a consequence, the resulting stress and strain on the above-the-ground prior art pool liners increased as the depth of water in the pool increased. Is it understood that if the stress and strain from the pressure created by the water in the pool exceeds a certain threshold, the seams (typically known as xe2x80x9cjoint seamsxe2x80x9d) that seal the liner sections together will leak or burst. This leakage in prior art pools typically occurred in the vertical sidewall of the liner especially when the static pressure of the water was augmented by the dynamic pressure created by people moving about in the pool.
In the prior art, a method used to counter or offset the harmful effects of the excessive water pressure on the sidewall of the pool was to increase the wall thickness and thus the strength of the liner. This prior art solution applied to any polymeric or plastic material. Thus, if the pool liner was a single sheet, i.e., single-ply, of polyvinylchloride (PVC), then the PVC sheet could be calendered thicker (where calendering is the manufacturing process of producing flexible PVC sheeting). In the limit, the point of diminishing returns was reached wherein calendering a thicker or heavier PVC liner sheet was no longer cost effective.
Another common technique employed in the prior art for producing stronger polymeric or plastic wall sheets involved bonding materials together in a lamination. This type of prior art lamination method is similar to lamination methods used in producing plywood sheets for the home construction industry.
In the plywood lamination method, two or more layers of thin wood were bonded together in a lamination resulting in plywood strengths far exceeding the sum total of the strengths of the individual layers. In the case of PVC laminations, it has been common practice in the prior art to sandwich a layer of synthetic fiber typically referred to as xe2x80x9cscrimxe2x80x9d between two PVC layers. An example of such a synthetic fiber sandwich known in the prior art includes a layer of polyester placed between two layers of PVC sheeting. The sandwich was then bonded together thermally and/or with an adhesive solution. Various lamination wall thicknesses with varying strengths could be achieved by varying the thicknesses of the PVC sheets and/or by varying the per square inch thread count of the scrim.
In the prior art, if (a) the single-ply PVC liner sheet is calendered thicker, or (b) the thickness of the PVC lamination is increased, unnecessarily high costs of materials are experienced if the increased thickness is applied to the entire sidewall. The strength required in the pool liner to offset the stress and strain of the water pressure is only required in the lower portion of the pool liner where the water pressure is the greatest. Consequently, if the increased thickness of materials is applied to the entire pool sidewall, the pool liner could be constructed to have a higher level of strength in the upper portion thereof then is necessary. This design of prior art pool liners can result in excessively high cost.
References describing flexible swimming pools of the prior art refer to single flexible plastic sheet components as being xe2x80x9cunitedxe2x80x9d. In the prior art, xe2x80x9cunitedxe2x80x9d components or sections enable the flexible pool apparatus to be assembled. The xe2x80x9cunitedxe2x80x9d portions are typically known in the prior art as a xe2x80x9cjoining seamxe2x80x9d. These xe2x80x9cjoining seamsxe2x80x9d are typically formed on relatively low power machines for this purpose (for example, ten kilowatt peak load having low pressure in pounds per square inch (psi) applied to PVC sheeting). Consequently, lower bonding heat is generated and less pressure is applied to the PVC sheeting materials so that all of the air gaps between the PVC sheet materials are not eliminated. The end result of this process produces a low power bond suitable for joining seams in products comprised of flexible PVC sheeting which do not require high strength seams or joints. Joining seams are low strength conventional seams known in the art and serve to join two or more plastic PVC pieces together. The bonding can be accomplished by the use of thermal, radio frequency (dielectric), ultrasonic and adhesive methods. In the thermal method, heat is employed to join (i.e., melt) the PVC sheeting components together. In the radio frequency or dielectric method, friction in the form of kinetic energy is generated within the PVC sheet materials that creates the bond. In the ultrasonic method, sound waves also create kinetic energy that enable the molecules of the two PVC sheets to marry together. Finally, use of adhesives serve to mechanically bond the two PVC sheets together.
Certain prior art patent references will be mentioned including U.S. Pat. No. 2,529,872 to Hasselquist, U.S. Pat. No. 2,551,673 to Hasselquist, and U.S. Pat. No. 1,961,061 to McCulloch. None of these patent references are directed to a large capacity swimming pool capable of containing a high volume of water. U.S. Pat. No. 2,529,872 to Hasselquist entitled Collapsible Container is prior art which specifically refers to portable wading pools, portable baths, wash tubs, and stock watering tanks. The single seals disclosed in Hasselquist ""872 are conventional xe2x80x9cjoining seamsxe2x80x9d located at separate locations. Seam 22 functions as a single conventional joining seam to connect the sidewall to the bottom piece. Seam 23 serves as a single conventional joining seam that forms the closure of an air chamber. Seams 15, 28 and 38 are also single conventional seams (in different embodiments) to serve to close an air chamber 16, 26 or 41. Each of these single conventional seams are located in different locations and assist in the assembly of the collapsible container. They do not serve a reinforcing function. The air chamber 16, 26 or 41 includes a vent 27 for trapping, not injecting, air therein. The drawing Figs. accompanying the ""872 patent specification illustrate two small children standing in a small child""s wading pool that has been filled by using a garden hose.
U.S. Pat. No. 2,551,673 to Hasselquist entitled Collapsible Container is prior art which also specifically refers to portable wading pools, portable storage tanks, baths, wash tubs, and stock watering tanks and containers. The ""673 patent specifically refers to providing improvements in the Hasselquist ""872 patent and thus discloses only single conventional joining seams for enabling the assembly of the wading pool. The joining seams are separated and are not used in any reinforcing capacity, for example, bottom circumferential seam 11. An annular sidewall 12 exhibits a double-walled construction and thus any reinforcing is provided by multiple full layers of material and not a reinforcing layer in combination with a plurality of reinforcing seals. The drawings accompanying the Hasselquist ""673 patent also illustrate a small child""s wading pool.
U.S. Pat. No. 1,961,061 to McCulloch entitled Collapsible Bathing Pool is prior art which specifically recites containers for water of a collapsible and portable nature. The different sections of water holding material are described as being xe2x80x9csuitable unitedxe2x80x9d which clearly indicates that the pool is assembled with single conventional xe2x80x9cjoining seamsxe2x80x9d. A plurality of reinforcing seals is not disclosed. A reinforcement of the sidewall is disclosed as being integral with one or more thicknesses of material from which the sidewalls are made. The reinforcement essentially is a separate sidewall layer, not a continuous reinforcing layer or strip including a plurality of reinforcing seals.
Thus, there is a need in the art for a large capacity reinforced swimming pool which exhibits a lamination-to-lamination bond about the horizontal perimeter of the pool which includes a continuous reinforcing layer and a first and second plurality of reinforcing seals which significantly improves the strength of the sidewall of the swimming pool against failure or bursting, while simultaneously providing a thin-walled, lightweight, robust, durable, flexible construction suitable for above-the-ground large capacity swimming pools containing a high volume of water.
Briefly, and in general terms, the present invention provides a new and improved large capacity reinforced swimming pool for use in the above-the-ground environment which includes a continuous reinforcing layer in combination with a first plurality of continuous reinforcing seals and additionally a second plurality of continuous reinforcing seals, each for reinforcing a continuous sidewall and for preventing the failure thereof due to excessive water pressure in a lower half of the large capacity reinforced swimming pool.
In a preferred embodiment, the large capacity reinforced swimming pool includes a flexible liner typically comprised of a suitable plastic such as polyvinylchloride (PVC) sheeting for containing a fluid such as water. The plastic liner is typically circular in shape but can also exhibit other shapes including a rectangular shape. The plastic liner includes a continuous sidewall and a single-ply bottom wall fused to the sidewall with a joining seam. In the preferred embodiment, the continuous sidewall is formed from a partial outer layer and a partial inner layer. Mounted on top of the flexible liner via a joining seam is an inflatable top ring that when charged with air causes the plastic liner to be supported in an upright position when the pool is filled with water.
In the present invention, the continuous sidewall is reinforced to counter the pressure applied to the sidewall of the plastic liner by the static and dynamic pressure of the water in the large capacity reinforced swimming pool. In order to accomplish this goal, the sidewall includes a separate continuous reinforcing layer bonded to the continuous sidewall via a first plurality of continuous reinforcing seals. To further increase the reinforcement, the continuous sidewall also includes a second plurality of continuous reinforcing seals which are located between the partial outer layer and the partial inner layer of the sidewall. The bottom wall is separately attached to the continuous sidewall at an interface between the partial inner layer of the continuous sidewall and the bottom wall by a joining seam.
The present invention is generally directed to an above-the-ground, large capacity reinforced swimming pool for use in the out-of-doors. The inventive large capacity reinforced swimming pool provides an attractive and economical solution to an otherwise persistent problem. The reinforcing components need only be applied to a lower half of the swimming pool where the pressure applied to the sidewall from the water is the greatest. Further, the reinforcing scheme utilized, i.e., the width of the continuous reinforcing seals, can be varied depending upon the size and water volume capacity of the pool. In its most fundamental embodiment, the large capacity reinforced swimming pool includes a flexible plastic liner for containing water. The liner includes a continuous sidewall and a bottom wall bonded to the sidewall by a joining seam. The continuous sidewall is formed from a partial outer layer and a partial inner layer. An inflatable top ring is mounted to the top of the sidewall for supporting the liner in an upright position. A continuous reinforcing layer is bonded to the continuous sidewall with a first plurality of continuous reinforcing seals for reinforcing the sidewall. A second plurality of continuous reinforcing seals located at an interface between the partial outer layer and the partial inner layer of the sidewall function to reinforce the sidewall. Each of the first and second plurality of reinforcing seals comprise at least two seals.